An ultrasound system has become an important and popular diagnostic tool since it has a wide range of applications. Specifically, due to its non-invasive and non-destructive nature, the ultrasound system has been extensively used in the medical profession. Modern high-performance ultrasound systems and techniques are commonly used to produce two or three-dimensional ultrasound images of internal features of a target object (e.g., human organs).
The ultrasound system may transmit ultrasound signals to a living body and receive ultrasound signals (i.e., ultrasound echo signals) from the living body by using an ultrasound probe. The ultrasound system may further perform various signal processing upon the ultrasound echo signals to form an ultrasound image.
The ultrasound system may perform a beam forming based on a mid-point algorithm corresponding to a focusing delay algorithm used to calculate a dynamic receive-focusing delay. The ultrasound system may further provide a Doppler image by using a pulse rate frequency higher than a generally usable pulse rate frequency to detect blood flow faster than the maximum detectable blood flow velocity at a deep depth of the living body. The Doppler image is a high pulse rate frequency Doppler image.
When the ultrasound signals are transmitted to the living body, the ultrasound echo signals are received from the living body and receive-focusing is performed upon the ultrasound echo signals based on the mid-point algorithm, a receive-focusing delay curve in a depth corresponding to a phantom sample volume is used due to a timing problem between a sample volume and the phantom sample volume. Accordingly, this presents a problem since an accurate receive-focusing delay curve corresponding to a reflecting position (i.e., depth) of the ultrasound echo signals is not applied and the sensitivity of Doppler signals is decreased.